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From Luca Morandini <lmorand...@ieee.org>
Subject Querying GeoJSON
Date Sun, 10 Aug 2014 04:51:47 GMT
I put Drill to the test on GeoJSON data (GeoJSON is, as the name implies, a way 
to serialize geo-spatial data in JSON, see an example at the end of this post), 
but found an issue.

The trouble is that geometry features are held in a vector, which is where all the 
selection should happen, but how I have to figure out how to do it.

I tried this statement:
select t.features.properties.name from dfs.`/opt/drill/sample-data/geo2.json` t;

but...
Query failed: Failure while running fragment. 
org.apache.drill.exec.vector.complex.RepeatedMapVector cannot be cast to 
org.apache.drill.exec.vector.complex.MapVector [4098f044-ebba-4ca4-8bec-c8b2760dd2ec]

Error: exception while executing query: Failure while trying to get next result 
batch. (state=,code=0)

While, specifying the vector index works as expected:
select t.features[0].properties.name from dfs.`/opt/drill/sample-data/geo2.json` t;

Help appreciated,

Luca Morandini
Data Architect - AURIN project
Melbourne eResearch Group
Department of Computing and Information Systems
University of Melbourne
Tel. +61 03 903 58 380
Skype: lmorandini

{
     "type": "FeatureCollection",
     "features": [
       { "type": "Feature",
         "geometry": {"type": "Point", "coordinates": [-75.343, 39.984]},
         "properties": {
           "name": "Location A",
           "category": "Store"
         }
       },
       { "type": "Feature",
         "geometry": {"type": "Point", "coordinates": [-75.833, 39.284]},
         "properties": {
           "name": "Location B",
           "category": "House"
         }
       },
       { "type": "Feature",
         "geometry": {"type": "Point", "coordinates": [ -75.534, 39.123]},
         "properties": {
           "name": "Location C",
           "category": "Office"
         }
       }
     ]
   }


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